I live in a very dry part of the Country so have several (9) water butts set up. When these are getting near full I usually take off several buckets full of water and stand them for later use, gaining a bit more. Last year I found a young Grass Snake under them, this was right up to the bungalow side, took some pics and left it be. We also get Frogs and Toads and I have created what I call "Toad Hall" - I bricked one course round a Manhole cover and put slabs over this leaving a space under these for them in the cool, it is also near to the small pond.